Uisce Éireann is asking the public to reduce water usage amid the current heatwave.
The appeal for water conservation comes as a new record for water consumption in a single day was set, with more than 693 million litres used in the Greater Dublin region alone.
Reservoir levels have been diminishing on peak demand days, with a reduction of up to 30 million litres recorded.
Uisce Éireann is asking people, businesses and farmers to reduce their water consumption by adopting water-saving habits, such as taking showers instead of baths and only using washing machines when they have a full load.
People in Dublin, Kildare, Meath and Wicklow have also been asked not to use hoses this weekend.
Head of Water Operations at Uisce Éireann, Margaret Attridge, said: "We know people want to enjoy their gardens and outdoor spaces during the good weather, but treated drinking water is a precious resource and demand is currently at record levels.
"We are asking customers to drop the hose and avoid using sprinklers, particularly for watering lawns. While grass may turn yellow during dry spells, it typically recovers quickly when rain returns.
"While the vast majority of customers across the country are not seeing any impact on their supply, night-time restrictions are now in place on 25 water supplies, out of more than 700 nationwide, as a precaution."
